The present disclosure generally describes communication networks, and more particularly data communication over best effort networks.
The rapid evolution of communication networks creates a significant demand for bandwidth from a service provider. A service provider can be a cellular operator, a Public Switched Telephone Network (PSTN) operator, a data network operator, an access network service provider, an Internet Service Provider (ISP), etc. A common network of a service provider can include a central premises, a plurality of intermediate nodes, and a plurality of subscribers. In a common network, one side of an intermediate node is connected to the customers or subscribers and the other side is connected to the central premises directly or via other intermediate nodes. The network that connects the central premises and the intermediate nodes can be referred to as the infrastructure of the service provider or, as the fixed network of the service provider.
An exemplary service provider can be an operator of wireless communication networks for mobile communications, such as but not limited to, the Global System for Mobile communications (GSM) networks, 3G networks, etc. A common fixed network of a wireless communication network operator can include a Radio Network Controller (RNC) located in a central premises and a plurality of node base stations (Node Base, Nb), which are spread all over the country as intermediate nodes.
Henceforth, the description, drawings and claims of the present disclosure may use the term RNC as a representative term for a central node and an Nb as a representative term for an intermediate node. Exemplary mobile terminals (MT) can be a cellular telephone or device, a PDA with cellular capabilities, or any other computerized device that can generate and/or receive audio, video, data or any combination thereof via a communication network such as but not limited to cellular network.
Usually, an RNC is used as an aggregation point for different types of data transferred to and from a plurality of MT. It can receive circuit switch telephony traffic as well as packet switched traffic traveling to and from the Internet, for example. Usually, a communication line between a central point and an intermediate node, or between intermediate nodes, can carry a plurality of communication sessions with different types of media. Different types of networks and protocols can be used over the communication lines. The communication lines can comply with different types of data link layer protocols, such as but not limited to: Time Division Multiplexing Access (TDMA), Asynchronous Transfer Mode (ATM), Ethernet, Internet, etc.
A growing number of communication links in an infrastructure of a service provider are based on the data link layer and/or network layer protocols that are “Best Effort Delivery” protocols. Exemplary best effort delivery protocols can be the ATM, the Ethernet, Internet, etc. A “Best Effort Delivery” network does not guarantee that data will be delivered during a certain period of time or that data will be delivered at all. In a best effort delivery network, users obtain best effort service, meaning that they obtain unspecified success, variable bit rate and unspecified delivery times. Thus, the current service depends on the current traffic load over the network. As a consequence, best effort delivery networks are more efficient and less expensive. On the other hand, the quality of service is reduced in that users may experience symptoms such as missing data, long delays, etc.
Because the current quality of service in a network depends on the current traffic load over the network, it would be effective for a common transmitting node to have the ability to sense the existence of any extra available bandwidth. The ability to sense the currently available bandwidth over the network can be used to utilize the available bandwidth in order to reduce delivery time of the data and to improve the user's experience (i.e., less delays in data delivery). Usually, such a method for sensing the existence of any extra available bandwidth is executed in higher layers of the OSI (Open Systems Interconnection) model, such as at the transport layer or at the application layer, for example.
Different methods are used to sense the existence of any extra available bandwidth. The TCP protocol, which is a connection-oriented protocol, starts with a high level of bandwidth consumption and then slowly reduces the bandwidth consumption according to the amount of detected packets lost. The bandwidth consumption is reduced until a steady state speed is reached in which packets are reliably delivered. Then, the process of sensing for the existence of any extra available bandwidth is executed by increasing the consumption in small percentages or increments at each cycle until an indication of a missed packet is received. Once an indication of a missed packet is received, then the missed packet is retransmitted and the bandwidth consumption is reduced. Consequently, the bandwidth consumption is alternated around the steady state value in a small percentage or increment depending on the current detection of missing packets. To prevent missing information, any missed packets are resent.
A common UDP does not attempt to sense for the existence of any extra available bandwidth, and therefore, it may lose an opportunity to increase its bandwidth consumption.
Common techniques for sensing the existence of any extra available bandwidth generally result in causing missing packets in their process. Thus, missing packets is a limitation of such common techniques. Further, these common techniques may increase the load on the network because retrials are needed to resend the missing information. In real time communication, missing packets can adversely affect the user's experience. For instance, in a voice communication session, the user may miss part of the conversation. In video sessions, to recover from a missing packet an Intra frame may be requested from the sender. An Intra frame is a compressed frame, which is not related to any previous frame, and therefore it requires more bandwidth and more computing resources. Therefore, there is a need in the art for a method and a system that can sense and utilize any extra available bandwidth over a best effort communication link without losing information.